Tension device for shears.



J. H. L W. W. STULL.

TENSION DBVIGEPQR sHEARs. APPLICATION FILED FEB. 6, `1905.

PATENTED JUNE 61,1905.y

abbot/www.

Ne. I791.590.

UNITED STATES Patented June 6, 1905.

PATENT OEEICE. .Y

JACOB H. S'IULL AND WILLIAM W. STULL, OF FREMONT, OHIO.

' TENSION DVICE FOR SHEARS- SPECIFICATION forming part of Letters Patent No. 791,590, dated June 6, 1905. i

Application filed February 6, 1905. Serial No. 244,352.

To all whom t may concern:

Be it known that we, JACOB H. STULL and WILLIAM W. STULL, citizens of the United States of America, and residents of Fremont, county of Sandusky, State of Ohio, have invented certainnew and useful Improvements in rlension Devices for Shears, of which the following' is a full and clear specication, reference being had' to the accompanying drawings, in which- Figure l is a perspective view of a pair o scissors provided with our improvement; Fig.

2, a detail perspective view of the Vvtensionspring; Fig. 3, a detail perspective view of the pivot-bolt removed; Fig. 4, a vertical longitudinal section, and Fig. 5 a transverse section taken through thepivot-bolt. Fig. 6 is a perspective View of a modified form of the tension-spring.

The object of this invention is to providea simple, durable, and inexpensive tension device which may be adjusted from time to time to obtain the desired tension on the cutting edges of the blades, as more fully hereinafter setforth.

To the accomplishment of this object and such others as may hereinafter appear the invention consists of the parts and combination of parts hereinafter fully described, and -particularly pointed out in the append ed claim, reference being had to the accompanying drawings, forming a part of this specification.A

Referring to the drawings by reference Characters, a designates a headed pivot which passes through the two blades and has its projecting portion flattened or made angular, as at 7), and its extreme end reduced in diameter and threaded, as at c,

A tension-nut 0l is tapped on the threaded extension c, and between this thumb-nut and the adjacent blade is arranged the tensionspring, which is of peculiar construction. This springis'constructed of a single blade of steel bent upon itself about midway its length to form two flat members e e', the underneath one lying fiat against the blade and the upper free member inclining upwardly and forwardly and bearing against the under side of the'thumb-n ut. The forward end of the lower membereis reduced in width and-bent downward, so as to form a finger f, which engages in a hole in the blade at a point forward of the pivot-bolt. The two members of this spring are provided with angular slots whichengage the angular projecting part of the pivot-bolt.

It will be observed that this tension device will draw the blades together with an even but resilient pressure, and this pressure may be regulated from time to time by the thumbnut to suit the notions of the particular user of the scissors, and the angular openings in the spring members and the engagement of the lower member positively with the adjacent blade absolutely prevent any turning action being imparted to the thumb-nut by the action ofthe blades, so that the nut will not be liable to Work loose. This construction is advantageous also for the reason that it permits a wide range of adjustment, as even though the upper member of the spring be adjusted far enough outward to pass off the angular part of the pivot the lower member will still engage the angular part of the pivot and prevent turning of the spring and accidental turning of the nut. The device is applicable to scissors and shears of the ordinary construction by simply boring a hole in the blade at a point beyond the pivot, as is obvious.

It will be obvious that we may strike up the projecting end of the pivot-bolt slightly to prevent the thumb-nut working off and becoming lost. It will be obvious also that the tension-spring may be made of a single piece -of spring-wire, as shown in Fig. 6, without departing from the invention. When thus made of wire, the lower member will be provided with two depend-ing fingers f instead of one, as shown in the otherviews. In this form the openings in the two members are angular, asin the Hat metal form, in order toembrace the angular part of the bolt and prevent it turning.

It will be apparent to those skilled in the art that various mechanical/embodiments of the invention are possible, and we therefore do not wish to be limited to the exact arrangement and construction shown.

What we claim, and desire to secure by Letters Patent, is-

A scissors or shears comprising two blades, a pivot extending therethrough and having its -eXtreme end reduced and threaded and the part adjacent to its threaded end made angular in cross-section, this angular part projecting beyond the blade, a thumb-nut on said threaded end, a tension-spring consisting of two inembers connected together at one end, the lower member lying against the face of the blade and having its forward end engaging a hole in the blade and the upper member bearing 

